The present invention generally relates to an image reading system capable of monochromatic reading and color reading.
A conventional color multi-function apparatus (MFP) capable of monochromatic reading and color reading has three kinds of modes consisting of a monochromatic mode (a monochromatic fixed mode), an ACS mode (a mode in which color/monochrome is determined every page) and a full color mode (a color fixed mode). If the SCS mode is set when a color/monochrome mixing original is color-copied, a “pre-scanning” operation is carried out prior to an actual scan every page in order to determine color/monochrome every page. If the time required to carry out the pre-scanning operation intends to be omitted, it is required to select the full color mode. However, if the full color mode is selected in the case of a color MFP having, e.g., a four-rotation drum, it is a waste of time since the color MFP always causes the drum to make four rotations even in the case of a monochromatic original.
On the other hand, in a case where a color scan is carried out by means of a low-price personal flat-bed scanner, an actual scan is often carried out after a pre-scan is carried out to verify the scanning condition of an original and after the user carries out a scan setting.
In addition, if resolution is increased (400 dpi through 600 dpi) when a color scan is carried out, there is a problem in that the file size increases. Moreover, in the case of a photographic image or the like, the JPEG compression is used for decreasing the file size. In this case, when compressibility is increased, there is not a serious problem if only the compressed image includes only a photograph, but there is a problem in that characters deteriorate if the compressed image include characters or the like.
As described above, if the conventional color image reading system reads an image at a high resolution (600 dpi or the like), the file size increases. Therefore, if the system is used as a network scanner, there is a problem in that it takes a lot of time to network-transfer a file, so that it is difficult for the user to process an image file after scanning. There is also a problem in that an HDD for storing image files must have a large capacity. Moreover, if a color/monochrome mixing original is scanned, it is required to carry out a pre-scan every page in order to determine color/monochrome every page, so that there is a problem in that it takes a lot of time to carry out processing.